1. Field of the Invention
The present invention relates to a setting tool for anchor rods of attachment anchors, which have a rear end section having a polygonal cross-section, with the setting tool including a housing provided with an insertion end receivable in a chuck of a percussion rotary drill, and a rod receptacle provided at an end of the housing opposite, in an axial direction, to the insertion end.
2. Background of the Invention
Attachment anchors represent attachment systems which includes an anchor rod and organic or inorganic mortar mass. The anchor rod is secured in a preliminary formed bore with a mortar mass. The anchor rod has, at its end projecting from the bore, load application means, e.g., an outer thread for attachment of a constructional element. For securing an anchor rod in a bore, first, the bore is filled with a mortar mass, and then the anchor rod is inserted into the bore filled with the mortar mass. For increasing the structural strength, usually, a filler material and/or aggregate is admixed to the mortar mass which makes the insertion of an anchor rod into a mortar-filled bore more difficult. The mortar mass and, if necessary, the filler mass and/or aggregate, on many occasions are contained in special containers which are placed into the bore in an untorn condition. The containers can be formed, e.g., as glass ampulla or foil sacks which should be broken when an anchor rod is inserted. Further, the mortar mass and the filler material and/or the aggregate has to be mixed very well to achieve a uniform distribution over the bore depth. When multi-component mortar systems are used, e.g., inorganic systems on a resin-hardener basis, as good as possible intermixing of components is necessary to insure a complete hardening of the mortar mass.
The mixing of the mortar mass and the filler material and/or aggregate is effected by rotating the anchor rod during its insertion into the bore. In addition to rotation about its axis, an anchor rod is subjected to axial impacts. The axial impacts promote the destruction of containers and facilitate the insertion of the anchor rod into a bore filled with a mortar mass, filler material and/or aggregate, and the residues of the containers.
The rotation of the anchor rod and the application of axial impacts is effected with a percussion rotary drill, e.g., a hammer drill of the assignee herein. Because anchor rods have no insertion ends adapted to be received in the chuck of a hammer drill, setting tools are used which are provided with an insertion end adapted to be received in the chuck of a hammer drill, on one hand, and with a receptacle for receiving the rear end of an anchor rod, on the other hand. The setting tool transmits a torque to the anchor rod as well as axial impacts generated by the hammer drill. To this end, the anchor rod is provided at its rear end with an end section having a polygonal, preferably, a hexagon cross-section. The receptacle has corresponding entraining surfaces in a form of a plug-in socket which cooperate with the surfaces of the rear end section of an anchor rod for transmitting the torque. The free end of the anchor rod end section is subjected to axial impacts generated by the hammer drill.
However, a drawback of the known setting tool consists in that the entraining surfaces of the receptacle can jam the corresponding entrained surfaces of the anchor rod end section. Therefore, it can be difficult to remove the setting tool after the anchor rod is set in. Therefore, as a rule, the removal of a setting tool should be delayed until the mortar mass in the bore hardens. Therefore, when a number of anchor rods need be inserted, always several setting tools should be available in order to be able to insert several anchor rods one after another without interruption. The force, which is required to pull the setting tool of the anchor rod, can result in loosening of an attachment anchor in a bore so that the attachment point does not have the required retaining value and becomes unfit.
German Patent No. 4,301,582 discloses a socket-like screw drill the receptacle of which has three rolling bodies aligned in an axial direction. The rolling bodies are spaced from each other by an angular distance of 120.degree. and radially arranged relative to each other with control surfaces. The radial adjustment of the rolling bodies takes place upon rotation of the screw drill housing. At that, an end of a screw inserted into the receptacle is clamped and is capable of transmitting a torque. The known screw driver is applicable for screwing-in processes without application of axial impacts. In case of application of axial impacts, the rolling bodies, which clamp the screw end, can dig into the entrained surfaces or be cold welded thereto as a result of application of pulsed impacts. The pulsed impacts can also result in deformation or even in destruction of the control surfaces which would adversely affect the functioning of the screw drill or would make it totally unfit.
Therefore, an object of the present invention is a setting tool for anchor rods of attachment anchors with which during rotational setting of an anchor rod with simultaneous application of axial impacts, jamming of the entrained surfaces of the anchor rod end section is prevented. The setting tool should be easily removable after the completion of a setting process and be immediately ready for an insertion of another anchor rod.